Stormont's two main parties have indicated the talks on paramilitary structures, welfare reform and dealing with the legacy of the past are nearing an end point.

Sinn Fein Deputy First Minister Martin McGuinness said yesterday the timeframe for reaching an overall deal is "days, not weeks".

And DUP Finance Minister Arlene Foster, who was acting First Minister until last week, said she believed the talks are "approaching the endgame".

Their predictions came after all five parties - also including Ulster Unionists, SDLP and Alliance - held a meeting on Tuesday in which the London and Dublin governments were not involved, according to senior sources.

With Secretary of State Theresa Villiers and Irish Foreign Minister Charlie Flanagan absent, the parties are believed to have discussed a possible timetable for closing down the negotiations. Mr McGuinness said he believed a deal was "achievable" and that the bilateral discussions were "intensifying".

But he also claimed there had been an attempt to "sabotage" the talks in the last few weeks.

"The best prospects for success in any negotiations is for all parties to come at them in good faith," he said.

"The difficulty about recent times is that some parties can't get out the door quick enough to say something which negatively feeds into what we're trying to do."

He pointedly told reporters in Parliament Buildings yesterday that neither his own party nor the DUP were responsible for the briefings. But he added: "I do think other parties have done that and it is not conducive to getting a good outcome."

Mrs Foster, meanwhile, also said she was "optimistic" about the talks but "there are still gaps to be closed".

The Stormont Assembly has been in disarray since the murder of a man by IRA members in August.

Kevin McGuigan (53), was shot dead in front of his wife in the staunchly republican Short Strand area of east Belfast in what police believe was a reprisal for the murder of a one-time associate and former IRA commander, Gerard 'Jock' Davison (47), three months earlier.

A police assessment that individual members of the Provisional IRA were involved in the shooting has piled pressure on Sinn Fein to explain how the supposedly defunct organisation still exists and prompted unionists to pull out all ministers but one from the Executive.

Sinn Fein has rejected the accusations and Mr McGuinness has challenged political rivals making claims about the party's links to criminality to "put up or shut up".

Prior to the McGuigan murder, the future viability of the institutions had already been in doubt as a consequence of long-standing budgetary disputes, with the row over the non-implementation of the Government's welfare reforms the most contentious.

The Stormont House Agreement was struck in December 2013 following weeks of intensive talks and included a package of measures designed to protect benefits claimants.

However, Sinn Fein pulled its support for welfare reform earlier this year, accusing the DUP of acting in bad faith.